Hydraulically-operated friction brake



March 23, 1954 WEE B ETAL 2,672,956

HYDRAULI CALLY- OPERATED FRICTION BRAKE Filed Feb. 5, 1952 3,Sheets-Sheet 1 March 23, WEBB T AL HYDRAULICALLYV- OPERATED FRICTION BRAKE 5 Sheets-Sheet 2 Filed Feb. 5, 1952 wiw BMW W hhm M 0 a if i 1 upy/ J w 7 k u w 1 z T a 1 m T Q a 2 rmvruvkv b L.

J. WEBB ET AL HYDRAULICALLY-OPERATED FRICTION BRAKE March 23, 1954 3 Sheets-Sheet 3 Filed Feb- 5, 1952 Patented Mar. 23, 1954 HYDRAULICALIiY-OPERATED FRICTION BRAK John Webb and Daniel Webb, LondonQEngland,

assignors' to The India & Telegraph Works '00 England, 'aiBritishe'o -Ru bber, Gutta- Perchampany Limited, London, mpany amass. February 5, 195 2,: Serial sateen c4 Claims priority, application Great Britain 5 February 13, 1951 s 'I'he'invention relates to hydraulically-operated friction brakes of the kind comprising a'friction disc or ring for attachment to the wheel or other member to be braked and for rotation therewith, two opposed friction pads for braking engagement with opposite side faces of the disc, meansfor holding the pads against rotation with the disc, andhydraulically operable means for effecting" inward movement of the pads to bring them into braking engagement with the disc. In some brakes'of this kind there are two or more discs or rings sideby side with additional friction" pads between them and the outer side faces'of" the assemblyare engaged by the friction pads asaforesaid," the inward movement of theipadsalso effecting inward movement of the discs into engagement 'with'the additional pads.

It is one object of the invention to provide an improved brake of the kind described especially suited for use with small wheelssuch as are employed on some high speed modern aircraft. More particularly the object is the provision of a brake of lightweight and small bulk which is capable of withstanding the high torque and of absorbing and/or dissipating at the necessary high rate thelarge-amount of heat'generated when an" aircraft is brake The invention consists in a brake of the kind described in which the means for holding the pads against'rotation comprise a fixed housing having throughways (later referred to a s'guideways) in the axial direction in which the pads are guided and constrained for sliding movement,

and in which the means for effecting inward movement of the pads comprisepiston and cylinder means hydraulically operable to cause relative expansive movement of the piston and cylinder in the axial direction of the disc and. two levers cooperating with the piston and cylinder and with the two friction pads respectively to convert outward expansive movement of the piston and cylinder into inward movement of the Dads.

Preferably the piston and cylinder means comprise a further throughway in the housing parallel to the aforesaid guide-Ways and constituting a cylinder, and two opposed pistons in the cylinder arranged for outward, expansive movement on admission of fluid to the cylinder between the pistons. In one construction thecylinder is radially within the guideways, the levers are fulcrumed at positions between the cylinder and the guideways for rocking movement about axes extending in the tangential direction, the outer ends of the pistons engage the radially 2 inner ends of the two levers respectively and the'outer ends of the, levers engage the pads so that outward movment of the pistons rocks the levers to move the pads inwardly towards one another into clamping engagement of the disc.

It is preferred that there are two housings with associated pads, levers and piston and cylinder means at diametrically opposed positions aroundythe-disc. o

There may be two friction discs side-by-side and the housing, or each housing when there are two, may have a tongue extending radially between the discs and provided with friction surfaces so that the friction pads operate to grip the discs against opposite faces of-the tongue respectively.

The housing or .each housing, may have two piston and cylinder means and associated levers circumferentially side-by-side and operating independently on asingle pad at each side of the disc or discs or on tw separate pads at each side.. i.

One specific construction of a brake according tothe inventionv will now be described by way of example, andwith reference to the accompanying drawings, in which:

'Figure 1 is a front view of the brake,

Figure 2 is a side view of the brake, part thereof being shown in section along the line 2-2 in Figure 1,- and Figure 3 shows diagrammaticallythe connection's-for fluid to the cylinders.

-The brakejorming the subject of this example is intended for use with a small aircraft wheel, part of which. is indicated in chain lines. The. brake ,hasitwo'x friction :rings ll, l2, constructed of copper and constituting the friction discs. The rings I I, I2 are positioned side-byside and each has key slots l3 cut in its outer edge for engagement with keys 20 formed on the inner surface of the wheel, the engagement preventing relative rotationbetween the discs and the wheel but permitting some degree of relative axial movement. 1

Arranged to lie within the compass of the wheel there is a plate-like member [4 having a central aperture I5 for passage of the fixed wheel axle and holes l6 for bolts by which the member I 4 may be secured to a flange on the axle and is held against rotation. The member l4 provides two diametrically extending arms I! and at the end of each arm there is a housing 18 integral with the member l4.

Each housing has a radial tongue I 9 which fits between the two copper friction rings H, I 2 and has riveted at 22 to its side faces pads 2| of friction material. Two guideways 23 are formed in the housingelfllopposite to the padsilaonthe aforesaid tongub lilfi T he se guideways zfiex tend in the axial direction of the assembly and have a cross-section of generally rectangular form with the length in the circumferential direction. The

outer side 24 of the cross-sectionis'ai iiate'about the axis of rotation. Received within each guideway 23 for sliding movement there -is a block 2 5 7 which carries on its inner ra'ce'a rriction ascafor engagement with the outer side face 21- of the adjacent disc ll, [2. Y

Formed in the housing I8 at positions radially within but close to the aforesaidgui'deways 23 in the axial direction and side-by-side circumferentially. These throughways 3| constitute two cylinders and within each cylinder there are-two opposed pistons 32 which are urged inwardly tow-ardsohe another round portions 34"of 1 the' pistons 32 f reduced diameter andreact against 1 inwardly directed flanges' 35 at themouths 'of th'e cylinders; lf'h'e inward movement of the' pistons 32- is limited Connections for an operating liquid'are made to one of the-twocylinders'm provided in each housing I8 and the two cylinders in each housing" are interconnect'ed at "44*: The connec- 41 Meansu ion bleeding air from the "other 0f the cylinders in each hcus'ingcarealsoprovided.

In the oper ation' 'of the brakeiliquid under pressure is admittedsto the'fourbylinder's 3 I and causes outward movement or the'l eight pistons"o 32. This movement rocks the eight'levers 41 to force-the slidingi blo'cks fi'inw'ardlyzso that each opposed pair of blocks" rings I H ,1 1-2 against the' central *tongues l 9 and provides-braking pressure-.

The arrangement by springs 33 which sur 2'5 clamps the friction there are two further throughways- 3=i extendingof: the: mechanism in each housing and the provision of two diametrically? opposed housings and associated mechanisms ensures a particularly even application of the braking..pressureand also enables --substanti-al areas of the discs to be exposed for cooling between the housings.

We claim:

A brake for braking a rotatable member against rotation relative to a second member, comprising in combination at least one friction disc having means for attaching. the disc to said rotatable member for-rotation therewith, two opposed friction pa'dsdispUsedOn opposite sides of said disc for' braki-ng engagement with opposite side faces thereof, a housing forked to provide two arms which embr'acethe-disc and formed with at least two aligned tubular guideways in the two arms respectively extending in the axial direction of the disc on opposite sides thereof, within which Iguidew'ayssaid pads are 'guided and constrained for sliding movement bythe walls of the guidewaysg meansror preventing rotationof said housingrelative to saids'econd member, said housing also being formed with a throughway radially withi'n'theguideways and extending parallel to the guidewa'ys; two opposed pistons in' said thro-ughway', th'e th'roughway constituting. a cyl-' in'der for the pistons; means for admitting. hy-

draulic fluid to the throughwa between; the pistonsto cause outward expansive movement'of the pistons in theaxial direction' of thedisc'ah'd two levers 'fulcrumedon the'housingatpositions between the throughway and the guideways for" rocking movement about'axes in the tangential direction, the outer ends'ofthepistons'eng'aging' the radially inner'erids'of thetwolevers'respectively and the outer ends of the levers engaging the two pads respectivel whereby outward movement of th'ep'istohs'rocks the levers to move the pads inwardly towards one another into clampingeng'ager'nent of'the'd'isc. OHNIW BB DANIEL WEBB.

lteferen'ce's Giteddn' the 'fil' bfthis patent UNITED STATES PATENTS Number Name-- Date 1,827,065 Brownyer Oct: 1-3, 1931 2115,0823 Pierce' Apr. 26; 1938" 2280599 Milan -A"'pr.'21, 1942- 2,-541,03l.- Butler Febrl3; l-

seamen-Parasite Number Country Date M 660,209 Great Britain-flue; 0011;31; 1951- 

